1. Field of the Invention
The present invention generally relates to battery powered units, and more particularly to a battery powered unit such as an electronic device which is powered by a battery and a resume process is positively carried out to resume the state at the time when the power source was turned OFF.
2. Description of the Related Art
Recently, there are various kinds of battery powered units such as hand-held computers, lap-top computers and palm-top computers, and these battery powered units are popularly used. In the battery powered unit, the power is turned ON/OFF frequently to minimize the discharge of the battery and to enable the normal operation of the battery powered unit to be carried out for a long time. For this reason, it is desirable that the state at the time when the power was previously turned OFF is restored when the power is turn ON, so that the operator may continue the operation from where he previously interrupted.
A battery powered unit having a resume function is conventionally known. The resume function saves predetermined information when the power is turned OFF by carrying out a suspend operation, and restores the predetermined information saved by the suspend process when the power is turned ON by carrying out a resume process. Hence, the resume function enables the battery powered unit to be used from the state at the time when the power was previously turned OFF.
However, the conventional battery powered unit carries out the above resume process independently of the remaining capacity of the battery. For this reason, the resume process may be carried out even when the battery has virtually no remaining capacity. In this case, the voltage supplied from the battery may decrease to a voltage which cannot drive the battery powered unit while the resume process is carried out. As a result, there are problems in that the resume process cannot be carried out in a normal manner when the power is next turned ON because the memory contents within the battery powered unit may be destroyed and the resume process may only be carried out half way due to the insufficient voltage supplied from the battery.